1. Field of the Invention
The present invention relates to an image capture apparatus for capturing an object image.
2. Description of the Related Art
Recently, a variety of digital cameras configured to capture a still image or moving image using a solid-state image sensor, such as a CCD (charge-coupled device), have been developed. However, the dynamic range of the solid-state image sensor is low compared to silver-halide film or the like. Accordingly, such digital cameras may produce degraded image quality depending on shooting conditions.
Therefore, in order to capture an image with a high dynamic range exceeding the dynamic range of the solid-state image sensor, a method of using a plurality of images having different luminance values and merging them together to maintain gradation without making any bright or dark image portion crashed or blurred has come into popular use.
In one example of this method, a plurality of pictures that have been sequentially captured at different time points are combined, as disclosed in Japanese Laid-Open Patent Application No. 5-007336.
In another example, a plurality of pictures having different luminance values are obtained using a plurality of image sensors having different sensitivity characteristics and are merged together to create a high-dynamic range image, as disclosed in Japanese Laid-Open Patent Application No. 7-203320.
However, in an image capture apparatus disclosed in Japanese Laid-Open Patent Application No. 5-007336, a plurality of pictures that have been captured at different exposures inevitably involve a time difference, so that an accurate composite image cannot be obtained. In addition, shooting a plurality of times takes time to complete.
In an image capture apparatus disclosed in Japanese Laid-Open Patent Application No. 7-203320, since a plurality of image sensors are used, the size or cost of the image sensors imposes a heavy burden on the image capture apparatus.